There are and were a lot of weapons that the troops loved, that the brass hated. Sometimes the troops hated a truly effective weapons system — like, for instance, the Sherman tank. There were tons of reasons that the Sherman “made sense” for an army that would be fighting thousands of miles overseas. Looked at from the Sherman crew perspective I can say that I don’t blame them.
The A-10 has lots of virtues. Chief among them is it’s ability to operate from relatively crude forward bases like Bagram. OTOH, it lacks the speed of an F-16 or F/A-18 to deliver ordnance to more distant locations where a company might be pinned down on a ridgeline. If the A-10 is already on-station great. But an intelligent enemy isn’t going to attack when it knows the A-10’s are around. So right away your preferred air platform in Afghanistan is handicapped.
There’s a bigger issue with the A-10 - it can’t really operate in an area where the US doesn’t have air supremacy because supersonic jets will likely blow it out of the sky. In areas where the US has air supremacy, it does very well.